Before you begin

You need to have a Kubernetes cluster, and the kubectl command-line tool must
be configured to communicate with your cluster. If you do not already have a
cluster, you can create one by using
Minikube,
or you can use one of these Kubernetes playgrounds:

Define a command and arguments when you create a Pod

When you create a Pod, you can define a command and arguments for the
containers that run in the Pod. To define a command, include the command
field in the configuration file. To define arguments for the command, include
the args field in the configuration file. The command and arguments that
you define cannot be changed after the Pod is created.

The command and arguments that you define in the configuration file
override the default command and arguments provided by the container image.
If you define args, but do not define a command, the default command is used
with your new arguments.

Note: The command field corresponds to entrypoint in some container
runtimes. Refer to the Notes below.

In this exercise, you create a Pod that runs one container. The configuration
file for the Pod defines a command and two arguments:

This means you can define an argument for a Pod using any of
the techniques available for defining environment variables, including
ConfigMaps
and
Secrets.

Note: The environment variable appears in parentheses, "$(VAR)". This is
required for the variable to be expanded in the command or args field.

Run a command in a shell

In some cases, you need your command to run in a shell. For example, your
command might consist of several commands piped together, or it might be a shell
script. To run your command in a shell, wrap it like this: